RSUs and ESPPs: the paycheck that arrives as stock (and the tax bill that arrives anyway)

By Tom, CPA · Updated October 25, 2026

TL;DR: RSUs are taxed as ordinary wages when they vest, at the shares' market value. Employers often withhold at a flat 22% federal rate, which can be well below your actual bracket. ESPP shares get favorable treatment only if you hold them 2 years from the offering date and 1 year from purchase. For most FIRE plans, the bigger risk isn't taxes. It's holding too much of one company.

Educational only, not tax, legal, or investment advice. Examples are illustrations, not predictions. Rules and limits change; verify current figures and talk to a qualified professional about your situation.

Restricted stock units feel like a gift: every quarter, shares appear in your brokerage account as if a polite elf delivered them. Then the tax return arrives and reveals the elf withheld less than you owed. And because the shares are your employer's stock, your paycheck, health insurance, and a growing chunk of your net worth all depend on the same company. Lavish Larry calls this "conviction." Frugal Fran calls it "one basket."

This guide covers federal tax rules for RSUs and employee stock purchase plans (ESPPs), plus the portfolio side, as of Oct 2026. Options are covered separately in ISOs vs NSOs.

CPA Warning Label: Vested RSUs are cash you chose to keep in one stock. If you wouldn't buy that much of your employer with a cash bonus, think hard about keeping it.

RSU taxation at vest

An RSU is a promise to deliver shares (or their cash value) once vesting conditions are met, usually continued employment over time.

• At grant: generally no tax. You haven't received anything yet.
• At vest/settlement: the fair market value of the shares delivered is compensation, reported as wages on your W-2 and subject to income tax withholding, Social Security and Medicare taxes.
• Basis: your basis in the shares equals the value included in income. Your holding period starts at vest.
• At sale: any change in value after vest is capital gain or loss, long-term if held more than one year (IRS Topic 409).

Because RSUs are taxed at vest, there's no tax advantage to holding vested shares. Selling immediately after vest typically produces little or no gain. Holding them is economically the same as receiving cash and buying your employer's stock with it.

An 83(b) election isn't available for RSUs in the usual case because no property is transferred at grant. Some private companies may offer deferral under Section 83(i), which has narrow eligibility rules.

Basis trap: brokers sometimes report an RSU sale on Form 1099-B with a basis of zero or a missing basis. If you don't correct it on Form 8949 using the vest-date value (often found on supplemental statements), you can pay tax twice on the same income.

Withholding shortfall

Employers commonly treat RSU income as supplemental wages. Under IRS Publication 15, employers may withhold federal income tax at a flat 22% on supplemental wages, and must use 37% on supplemental wages above $1 million in a calendar year.

The problem: if your marginal bracket is 32%, 35% or 37%, a 22% flat withholding leaves a gap, plus whatever your state does. As of tax year 2026, the 32% bracket starts at $201,775 of taxable income for single filers and $403,550 for joint filers (IRS Rev. Proc. 2025-32).

Illustration: A single filer with $210,000 of salary vests $80,000 of RSUs. Much of that RSU income falls in the 32% and 35% brackets. Withholding at 22% is $17,600. If the actual federal tax on the extra $80,000 is about $25,500 (some at 24%, most at 32%, the rest at 35%), the gap is nearly $8,000, before any state tax. Multiply by four quarterly vests and the April surprise gets large.

Ways people handle it:

• Increase W-4 withholding from regular paychecks.
• Make quarterly estimated payments.
• Sell enough shares at vest to set cash aside for the gap.
• Check whether the employer lets you elect a higher withholding rate on RSUs. Some plans do.

Paying enough through withholding and estimates generally avoids an underpayment penalty under the IRS safe harbors. Those rules are worth reviewing in a big vest year.

ESPP qualifying dispositions

A tax-qualified ESPP under Section 423 lets employees buy company stock through payroll, often at up to a 15% discount, and many plans include a lookback that uses the lower of the price at the start or end of the offering period. Under §423, purchases are limited to $25,000 of stock (measured at grant-date value) per calendar year.

No tax applies at purchase. What happens at sale depends on holding periods (§423(a)):

• Qualifying disposition: sold more than 2 years after the grant (offering) date and more than 1 year after purchase. Ordinary income is the lesser of (1) the actual gain (sale price minus purchase price) or (2) the discount measured at the offering date. The rest is long-term capital gain.
• Disqualifying disposition: sold earlier. Ordinary income is the full spread at purchase (fair market value on the purchase date minus the price paid), even if the stock later fell. Any additional gain or loss is capital.

Your employer issues Form 3922 with the dates and values you need. Ordinary income from ESPP sales generally appears on your W-2, but your 1099-B basis may need adjusting.

The FIRE reality: the discount is a reliable gain, while the qualifying holding period is a bet on one stock. Many people sell soon after each purchase, accept ordinary income on the discount, and diversify.

Concentration risk

Single stocks can fall a long way and stay down. Your employer's stock is uniquely risky for you because a bad stretch for the company can hit your job and your portfolio at the same time.

• Set a cap, such as no more than 5% or 10% of investable assets in any single stock, and write it down.
• Have a default rule for each vest, such as "sell at vest, reinvest in the index funds."
• Be aware of company trading windows and blackout periods. Some employees use preset 10b5-1 trading plans.
• In taxable accounts, sell shares with the highest basis first when trimming. Specific identification of lots helps; see the taxable brokerage guide.

The "but it keeps going up" objection is common and understandable. Diversifying isn't a prediction that the stock will fall. It's insurance against a scenario you can't afford.

Example

Illustration: Fran receives a quarterly vest of 200 RSUs at $150, which is $30,000 of wages. Her employer withholds 22% federal by selling shares, about 44 shares, and delivers the remaining 156 shares with a basis of $150 each.

• She sells all 156 shares the next day at $151: a $156 short-term gain. That's essentially no tax drama, and she reinvests about $23,500 into her three-fund portfolio.
• Her marginal federal rate is 32%, so she adds about $3,000 to her next estimated payment to cover the withholding gap of roughly 10 percentage points.

ESPP: she buys 100 shares at $85, a 15% discount on an offering-date price of $100, while the market is $110 on the purchase date. If she sells right away at $110, she has $2,500 of ordinary income (the $25 spread × 100) and no capital gain. If she instead waits for a qualifying disposition and sells at $130, ordinary income is the lesser of the actual gain ($4,500) or the offering-date discount ($15 × 100 = $1,500). So $1,500 is ordinary and $3,000 is long-term capital gain, if the stock cooperates.

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